90 Oh the Anliquity of the Areometer, 



This notice is not accurate, if the poem De Ponderibs et Menfuris, printed at the end of 

 the works of Prifcian, and admitted by all the learned to have been written by Rhemniu& 

 Fannius Palaemon be truly afcribed to that grammarian : Rhemnius lived under Tiberius, 

 Caligula, and Claudius Ca;far, and, confequently, was three centuries anterior to Hypacia. 

 The follow ing is the defcription which he gives of Areometry, which is equally valuable 

 for its per fpicuity and exaftnefs: 



Ducitur argento tenuive ex sere cylindrus, 

 Quantum inter nodos fragilis producit arundo, 

 Cui cono interius modico pars ima gravatur 

 Ne totus fedeat, totufve fupernatet undis, 

 * Lineaque a fummo tenuis defcendit ad ima, 



Dufla fuperficie, tot quaeque in frufta fecatur 

 Quot fcruplis gravis eft argenti serifve cyliudrus. 

 Hoc, cujufque potes pondus fpeftare liquoris. 

 Nam fi tenuis erit, majori immergitur unda ; 

 Sin gravior, plures modulos fuperefle notabis. 

 Aut fi tantumdem laticis fumatur utrinque 

 Pondere prseftabit gravior ; fi pondera fecum 

 Conveniunt, tunc major erit quae tenuior unda eft. 

 Quod fi ter feptem numeros texifle cylindri, 

 Hos videas latices, illos cepifle ter odto. 

 His drachma gravius fatearis pondus inefic". 

 Sed refert sequi tantum conferre liquoris, 

 Ut gravior fuperet drachma, quantum expulit undae 

 Illius aut hujus, teretis parfima cylindri*. 



It cannot, therefore, be doubted but the Areometer was an inftrument well known, and 

 commonly ufed, three hundred years before the birth of Hypacia. It is difficult to conceive 

 how Synefius, contemporary and friend of this celebrated lady, could attribute the invention 



* In EngliQi, " A cylinder is made of filver, or thin brafs, in length equal to the diftance between the knots of 

 a brittle reed. The lower pwt is loaded within, fo that it fcall neither totally fink, nor entirely float. A fine 

 line is drawn from the upper to the lower extremity of its furface, and divided into as many portions as the 

 fcruptes which exprefs the weight of the cylinder. With this inftrument the relaiive wtight of any fluid may 

 be afcertained : for, if it be light, the cylinder will fink deeper ; or, if heavy, the number of divifions above the 

 furface will be more confiderable. If equal bulks of different fluids be taken, the denftft will exceed the 

 ether in weight ; or, if the weights be equal, the rareft fluid will occupy the greater fpsce. For example, if 

 the cylinder be found to fink through twenty-one divifions in one fluid, and in another through twenty-four, 

 it may be concluded, that the heavier exceeds the other by three fcruples, or one drachm. But, it is more ac- 

 curate, inftead of attending to the difference, to compare the two fluids, by attending to the quantities of each 



to magnitude, which arc difplxced by the immerfc^ pact of the cylinder.'' 



to 



